Pengaruh Konsentrasi Asam Terhadap Sifat Fisik dan Muatan Permukaan Selulosa Termodifikasi

Agus Wedi Pratama, Bambang Piluharto, Dwi Indarti, Tanti Haryati, Hardian Susilo Addy

Abstract

Selulosa merupakan salah satu biopolimer melimpah yang banyak digunakan dalam berbagai bidang seperti kertas, energi dan material komposit. Hidrofilisitas, dapat diperbaharui, ramah lingkungan dan aman adalah sifat-sifat selulosa yang dapat berpotensi menjadi material maju. Berdasarkan sifat-sifatnya, selulosa dapat dimodifikasi untuk menghasilkan sifat fungsional yang sesuai dengan aplikasinya. Dalam penelitian ini, selulosa mikrokristalin (MCC) dimodifikasi melalui metode hidrolisis asam. Prinsip metode ini adalah penghilangan bagian amorf pada selulosa oleh asam, meninggalkan bagian kristal. Selain itu, ketika asam digunakan sebagai agen hidrolisis, maka akan menghasilkan muatan permukaan pada selulosa. Dalam penelitian ini, pengaruh berbagai konsentrasi asam pada struktur kimia, kristalinitas, morfologi dan muatan permukaan telah dikaji. Perubahan struktur selulosa dianalisis menggunakan Fourier Transform Infra Red (FTIR), kristalinitas menggunakan X-ray Diffraction (XRD), morfologi menggunakan Scanning Electron Microscopy (SEM) dan muatan permukaan menggunakan titrasi konduktomteri. Hasil analisis FTIR menunjukkan masuknya gugus sulfat pada struktur selulosa. Analisis XRD menunjukkan peningkatan kristallinitas dalam selulosa termodifikasi seiring bertambahnya konsentrasi asam. Hasil analisis morfologi menunjukkan partikel dalam selulosa termodifikasi (CM) lebih tersebar daripada MCC. Analisis titrasi konduktometri menunjukkan bahwa mengalami peningkatan muatan permukaan pada CM seiring dengan bertambahnya konsentrasi asam. Oleh karena itu, dapat disimpulkan bahwa pengaruh konsentrasi asam sulfat pada hidrolisis selulosa memberikan dampak yang signifikan pada sifat fisik dan muatan permukaan.

Effect of Acid Concentration on Physical Properties and Surface charge of Modified Cellulose. Cellulose is one of abundant biopolymer that many widely used in various applications such as paper, energy and composite material. Hydrophilicity, renewable, biodegradable, and safety are cellulose properties that can became potential of advance materials. In the utilization, cellulose can be modified its properties for different purposes. In this work, microcrystalline cellulose (MCC) was modified by acid hydrolysis method. The principle of this method is removed amorphous region of cellulose by acid and leaving crystalline phase. Moreover, when acid was used as hydrolyzing agent, it produce the surface charge on cellulose. In this research, the effect of various concentration of acid on the chemical structure, crystallinity, morphology and surface charge have studied. The chemical structures were analyzed using Fourier Transform Infra Red (FTIR), crystallinity using X-ray Diffraction (XRD), morphology using Scanning Electron Microscopy (SEM), and surface charge using titration conductometric. The FTIR analysis result has successfully showed the entry of sulfate groups on the cellulose structure. The XRD analysis showed increasing crystallinity in Cellulose Modified (CM) with increase acid concentration. By morphology analysis, particles in CM more disperse than MCC. Analysis of conductometric titration shows that there is an increase in surface charge in CM as acid concentration increases. Thus, the effect of sulfuric acid concentration on hydrolysis of cellulose has a significant impact on physical properties and surface charge.

Keywords

hidrolisis asam; kristalinitas; muatan permukaan; selulosa termodifikasi

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